1. Technical Field
The disclosure generally relates to spinal surgery.
2. Description of the Related Art
The human spine is composed of a column of thirty-three bones, called vertebrae, and their adjoining structures. The twenty-four vertebrae nearest the head are separate bones and are capable of individual movement. These vertebrae are generally connected by anterior and posterior longitudinal ligaments and by discs of fibrocartilage, called intervertebral discs, positioned between opposing faces of adjacent vertebral bodies. The remaining nine vertebrae are fused to form the sacrum and the coccyx and are incapable of individual movement. The vertebral body and the dorsal vertebrae enclose an opening termed the vertebral foramen, through which the spinal cord, a column of nerve tissue which communicates nerve impulses between the brain and the rest of the body, and spinal nerve roots pass and are protected from damage.
In this regard, FIG. 1 is a schematic diagram depicting three representative vertebrae (10, 12 and 14), associated intervertebral discs (16 and 18), spinal cord 20 and various spinal nerves (22, 24 and 26). In contrast, FIG. 2 depicts vertebrae 14 and the spinal cord 20 in greater detail. Specifically, an opening (e.g., a tear 28) in the dural sac 30, which surrounds the spinal cord, is evident. Notably, nerve rootlets (e.g., rootlet 32) extend from the opening, owing primarily to the outward flow of spinal fluid from the opening.